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Ecdysone-induced expression of the caspase DRONC during hormone-dependent programmed cell death in Drosophila is regulated by Broad-Complex

2002; Rockefeller University Press; Volume: 157; Issue: 6 Linguagem: Inglês

10.1083/jcb.200201034

1540-8140

Dimitrios Cakouros, Tasman Daish, Damali N. Martin, Eric H. Baehrecke, Sharad Kumar,

Invertebrate Immune Response Mechanisms

The steroid hormone ecdysone regulates both cell differentiation and cell death during insect metamorphosis, by hierarchical transcriptional regulation of a number of genes, including the Broad-Complex (BR-C), the zinc finger family of transcription factors. These genes in turn regulate the transcription of a number of downstream genes. DRONC, a key apical caspase in Drosophila, is the only known caspase that is transcriptionally regulated by ecdysone during development. We demonstrate that dronc gene expression is ablated or reduced in BR-C mutant flies. Using RNA interference in an ecdysone-responsive Drosophila cell line, we show that DRONC is essential for ecdysone-mediated cell death, and that dronc upregulation in these cells is controlled by BR-C. Finally, we show that the dronc promoter has BR-C interaction sites, and that it can be transactivated by a specific isoform of BR-C. These results indicate that BR-C plays a key role in ecdysone-mediated caspase regulation.